Dama Gazelle
The dama gazelle, addra gazelle, or mhorr gazelle (Nanger dama, formerly Gazella dama) is a species of gazelle. It lives in Africa in the Sahara desert and the Sahel. This critically endangeredspecies has disappeared from most of its former range due to overhunting and habitat loss, and natural populations only remain in Chad, Mali, and Niger. Its habitat includes grassland, shrubland, semi-deserts, open savanna and mountain plateaus. Their diets includes grasses, leaves (especially Acacia leaves), shoots, and fruit. In Niger, the dama has become a national symbol. Under the Hausa name meyna or ménas the dama appears on the badge of the Niger national football team, who are popularly called the Ménas. Description The largest of all gazelle species, the dama gazelle has at least two subspecies, which vary greatly in colour. The eastern subspecies, known as the red-necked gazelle (Gazella dama ruficollis), is bright white with a reddish-brown neck. However, the degree of colouration increases from east to west, and the most westerly subspecies, the Mhorr gazelle (Gazella dama mhorr), is almost completely red, apart from the undersides and the rump. It has a small white patch on the throat, and a white face, with red cheek patches and thin black stripes running from the eyes to the corners of the mouth. All dama gazelles have thin legs and a long, slender neck, as well as long, S-shaped horns, which are larger and thicker in males. Biology Dama gazelles form mixed herds of 10 to 20 animals which roam widely to find enough vegetation and water to survive. They migrate seasonally, forming larger groups of several hundred, in which they move north into the Sahara desert at the start of the rainy season and back south into the Sahel for the dry season. They feed on acacia, bush leaves and grasses, and may stand on their hind legs to reach higher foliage. Dama gazelles are preyed upon by cheetahs, African Wild Dogs, lions, leopards, hyenas and jackals. Females reach sexual maturity at nine to twelve months and males between 18 and 24 months. Breeding takes place between March and June, and a single calf is born six and a half months later. Initially the newborn calf is hidden from the herd, but begins to follow its mother after a few days. The calf will be weaned at around six months old. Males are territorial during the breeding season, when they guard several females, and will mark their territory with faeces, urine, and secretions from the preorbital glands beneath the eyes. Range and Habitat Once a numerous and widespread animal, the dama gazelle was found from Morocco, Senegal and Mauritania eastward to the Sudan. It suffered a serious decline in recent years and is now found only in Chad, Mali and Niger. Recent surveys in these three countries found very few gazelles, making the dama one of the most threatened species in Africa. Captive-bred groups of the Mhorr gazelle have been reintroduced into fenced areas in Senegal, Morocco and Tunisia. Formerly widespread in the Sahara and Sahel zones, but their range and numbers have been extremely reduced. In North Africa, Dama Gazelle are now probably extinct, although they may survive in the Dra (where observations were made by nomads in 1993) (Cuzin 1996; Aulagnier et al. 2001). It is also possible, though increasingly unlikely, that they may survive in very small numbers along the border between southern Morocco and Mauritania (Cuzin et al. in press). They may also survive in the Tassili de Tin Rehror in southern Algeria (K. De Smet pers. comm.). In Tunisia, they are believed to have occurred in the south and to have disappeared before the 20th century (Smith et al. 2001). South of the Sahara, Dama Gazelle are still present in eastern Mali, Air and Termit/Tin Toumma in Niger, and in the Chadian Manga and Ouadi Rim Ouadi Achim Nature Reserve in Chad (Scholte in press, and references therein); however, aerial and ground surveys of Termit-Tin Toumma in 2007 failed to record any Dama Gazelles (Wacher et al. 2007). They are now thought to be extinct in Mauritania, and are probably extinct in Nigeria, Burkina Faso, and Libya (see Scholte in press for summary, and references therein). There are no recent confirmed records from the Sudan, although East (1999) mentioned it could still occur at low densities in Northern Darfur and Northern Kordofan. Inhabits Sahelian grasslands, sparsely wooded savanna and sub-desert steppes with Acacia and Panicumvegetation; usually avoids really sandy areas, but will frequent low mountains and mountain plateaus, probably as refugia. In southern Morocco, it was found in areas without any Acacia, but with dense shrub cover (Cuzin 2003). Generally, Nanger dama is found in arid areas with sparse vegetation. However, its habitat changes slightly throughout the year, as this animal migrates seasonally. Dama gazelles resides on the pastures and plateaus of the Sahara desert during the rainy season, and move to the open bushlands in the dry season. This species avoids the mountains and dunes of the region, instead opting for the flatter, stonier plains. Unfortunately, due to overgrazing by livestock, land development by humans, and long term climate change, the habitat of N. dama has become even drier and somewhat less suitable through the years. Morphology Nanger dama has a body with lean legs and a long slender neck. Its glossy coat is characterized by patches of reddish-brown and white. Its face and undersides are always white, its neck is reddish-brown, and its throat always bares a white patch. However, color varies between sub-species. Nanger dama mohrr, the western sub-species, is almost completely red, excluding its undersides and posterior. It also boasts red cheek patches and black stripes which trace from its eyes to the corner of its mouth. The eastern sub-species, Nanger dama ruficollis is mostly white, with its reddish-brown color only showing on its neck and back. These animals possess horns that are shaped like the letter S; they point back and curl upwards. The horns generally range from 25 to 35 cm in length, with males possessing slightly larger sets than females. They are also sexually dimorphic in size, with females usually weighing 35 to 40 kg, and males ranging anywhere from 40 to 75 kg in weight. Their basal metabolic rate is relatively high given their body size, as is often the case for members of Artiodactyla. Behavior Most communication in this species is through body language. For example, erect posture in males demonstrates aggressiveness and high rank, and is also used in sexual displays. Males may also angle their heads or ram bushes so as to draw attention to their horns. Submission, on the other hand, is often represented by lowering of the head, or by jutting of the chin. Turning or moving away are also employed as ways to indicate submission. These animals utilize scent as well, as all members of a tribe urinate and defecate as a way of marking their territory against outsiders. Males have been known to snort or sputter during sexual displays. Reproduction The mating season can begin as early as August and end as late as October. During this time, males become territorial and engage in behaviors that indicate their aggressiveness and status. They usually urinate or defecate to mark their territory and horn the grass to advertise their strength and high status. Males also herd and chase to keep females in their vicinities and other rival males away. The courtship behaviors of males usually include prancing, nose-lifting, upright posture, kicking of their forelegs, and touching, nibbling, or licking of the female with their muzzles. Some males may even resort to sputtering or snoring to get the attention of a mate. A receptive female often walks in circles, makes sharp turns, and holds out her tail to indicate that she is ready to mate. The male mounts by standing behind her on his hind legs, with his forelegs curled in toward his own body. It is common for the female to continue moving during copulation. Mating System: polygynous ; cooperative breeder Mating generally occurs between the months of August and October, although it has been known to occur year-round in captivity. The estrous cycle of female N. dama usually lasts about 19 days, although it can be as short as 16 days or as long as 22 days. Generally, this species gives birth to one offspring at a time, although in rare circumstances, twins are born. Immediately after birth, mothers keep newborns sequestered from the rest of the herd. After a few days, however, the young are usually strong enough to follow their mothers around the grasslands and be seen by other members of the herd. Breeding interval: Dama gazelles breed once a year. Breeding season: In the wild, mating usually occurs between the months of August and October. Range number of offspring: 1 to 2. Average number of offspring: 1. Range gestation period: 5.5 to 6 months. Range weaning age: 3 to 4 months. Range age at sexual or reproductive maturity (female): 1.5 to 2 years. Average age at sexual or reproductive maturity (male): 1 years. Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous The mothers of this species invest lots of energy in protecting their young. It is quite common for two females to team up in defending their offspring, as pairs of females can often be observed chasing and attacking jackals that are hunting young gazelles. Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Protecting: Female); post-independence association with parents Category:Mammals Category:Herbivores Category:Gazelles Category:Antelope Category:African-Animals